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authorSasha Levin <levinsasha928@gmail.com>2011-07-18 16:17:15 +0200
committerAvi Kivity <avi@redhat.com>2011-09-25 18:17:57 +0200
commit8c3ba334f8588e1d5099f8602cf01897720e0eca (patch)
tree3f195eba4ff341817990db4b60c4aae829a80d82 /arch
parentKVM: MMIO: Lock coalesced device when checking for available entry (diff)
downloadlinux-8c3ba334f8588e1d5099f8602cf01897720e0eca.tar.xz
linux-8c3ba334f8588e1d5099f8602cf01897720e0eca.zip
KVM: x86: Raise the hard VCPU count limit
The patch raises the hard limit of VCPU count to 254. This will allow developers to easily work on scalability and will allow users to test high VCPU setups easily without patching the kernel. To prevent possible issues with current setups, KVM_CAP_NR_VCPUS now returns the recommended VCPU limit (which is still 64) - this should be a safe value for everybody, while a new KVM_CAP_MAX_VCPUS returns the hard limit which is now 254. Cc: Avi Kivity <avi@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Suggested-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/kvm_host.h3
-rw-r--r--arch/x86/kvm/x86.c3
2 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index dd51c83aa5de..c00ec28e7147 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -26,7 +26,8 @@
#include <asm/mtrr.h>
#include <asm/msr-index.h>
-#define KVM_MAX_VCPUS 64
+#define KVM_MAX_VCPUS 254
+#define KVM_SOFT_MAX_VCPUS 64
#define KVM_MEMORY_SLOTS 32
/* memory slots that does not exposed to userspace */
#define KVM_PRIVATE_MEM_SLOTS 4
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2b76ae3cb501..41dfebea6218 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2086,6 +2086,9 @@ int kvm_dev_ioctl_check_extension(long ext)
r = !kvm_x86_ops->cpu_has_accelerated_tpr();
break;
case KVM_CAP_NR_VCPUS:
+ r = KVM_SOFT_MAX_VCPUS;
+ break;
+ case KVM_CAP_MAX_VCPUS:
r = KVM_MAX_VCPUS;
break;
case KVM_CAP_NR_MEMSLOTS: